Lubricant for conveying containers

ABSTRACT

The passage of a container along a conveyor is lubricated by applying to the container or conveyor a lubricant composition comprising a water-miscible silicone material having a silicone emulsion wherein the silicone emulsion contains less than 500 ppm of a triethanolamine salts of alkyl benzene sulfonic acid compounds.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/080,000, filed Mar. 15, 2005, titled DRY LUBRICANT FORCONVEYING CONTAINERS, the entire disclosure of which is incorporatedherein by reference.

FIELD OF THE INVENTION

This invention relates to conveyor lubricants and to a method forconveying articles. The invention also relates to conveyor systems andcontainers wholly or partially coated with such lubricant compositions.

BACKGROUND

In commercial container filling or packaging operations, the containerstypically are moved by a conveying system at very high rates of speed.Lubrication may be provided by diluting a concentrated lubricantcomposition with water to form an aqueous dilute lubricant solution(i.e., dilution ratios of 100:1 to 1000:1), and dispensing copiousamounts of aqueous dilute lubricant solution to the conveyor orcontainers using spraying or pumping equipment or by using a undilutedor “dry lubricant.” These lubricant compositions permit high-speedoperation of the conveyor and limit marring of the containers or labels.

Conveyor lubricants are constantly evolving in an effort to meetincreasing demands from filling and packaging plants. Specifically, thestandards that conveyor lubricants have to meet in terms of (1) PETcompatibility, (2) the environment surrounding a conveyor line, (3) costof the lubricant composition and dispensing the lubricant composition,and the cost of using high amounts of water, and (4) the lubricantdispensing system complexity are becoming more rigorous. Silicone basedconveyor lubricants have been seen as meeting some of the increaseddemands, however, there remains a need for even better silicone basedconveyor lubricants that do not adversely affect the environmentsurrounding the conveyor line, that are cost effective from acomposition and dispensing point of view, that are compatible with PETmaterials, and that are not difficult to dispense.

The compatibility of lubricant compositions with poly(ethyleneterephthalate) (PET) is recognized as being important in the prior artboth in aqueous dilute lubricants and dry lubricants. However, few priorart teachings measure PET compatibility in terms of bottle failure. Whatis important in regards to PET compatibility is that PET beveragebottles filled with carbonated beverages and exposed to conveyorlubricant solutions do not show failure under storage. By failure it ismeant that the filled bottle bursts or leaks and the contents exit fromthe bottle. The important measure of the PET compatibility of alubricant formula is the relative failure rate of bottles exposed to thelubricant. In most prior art publications, PET compatibility is judgedby the visual appearance of bottles that have been contacted withlubricant solutions under conditions under which bottles typically donot fail. These prior art teachings assume a correlation exists betweenthe visual appearance of bottles and failure rates when there is in factno correlation between the appearance of bottles and bottle failurerates. Examples described in patent application Ser. No. 11/233,596,titled SILICONE LUBRICANT WITH GOOD WETTING ON PET SURFACES, andexamples described in patent application Ser. No. 11/233,568 titledSILICONE CONVEYOR LUBRICANT WITH STOICHIOMETRIC AMOUNT OF AN ACID,present meaningful PET compatibility test results. In examples describedin these two documents it is evident that there is no correlationbetween the visual appearance and the failure rate of bottles that havebeen contacted with lubricant compositions.

In some patents, PET compatibility is addressed in part by preferringthat contact be avoided between the lubricant composition and portionsof thermoplastic containers that are prone to stress cracking, forexample the amorphous center base portion of the container. However, inactual practice, it is difficult to prevent lubricant compositions fromcontacting amorphous stress crack susceptible portions of the bottle andit is instead preferred that the lubricant have a high degree of PETcompatibility as measured by a PET compatibility test that evaluatesfailure rate.

Silicone lubricants have been used on conveyors because they werebelieved to be PET compatible under the prior art understanding of PETcompatibility as determined using a visual test as opposed to a failuretest. Also, silicone lubricants were desirable because they providedadequate lubricity on conveyor surfaces. Silicone lubricants include asilicone material that is typically part of a silicone emulsion. Inaddition to the actual silicone material, a silicone emulsion alsoincludes an emulsifier that allows the silicone raw material to go intosolution when formulating. The emulsifier is often a surfactant, and ithas been discovered in the present invention that some surfactants usedin the emulsion may promote stress cracking in PET containers.

As previously discussed, conveyor lubricants may be used as both adiluted lubricant composition or an undiluted or “dry” lubricantcomposition. Diluted lubricants are advantageous because they are aneffective way of lubricating conveyor surfaces while using less of theconcentrated lubricant composition. On the other hand, dry lubricantsare seen as advantageous because diluting lubricants with copiousamounts of water is wasteful, environmentally unfriendly, and costly.The presence of wet surfaces and standing water provides a medium forthe growth of microorganisms including bacteria, yeast, and mold.Puddles of excess lubricant solution on floors create a hazard forslipping and falling. By requiring dilution of the concentratedlubricant, dilution errors can occur, leading to variations and errorsin the concentration of the aqueous dilute lubricant solution. Dilutionof concentrated lubricant compositions on a conveyor line requires useof equipment that increases system complexity, requires additionalmaintenance, and may fail or function incorrectly. Water used fordilution of concentrated lubricant solutions on site can causeenvironmental stress cracking of poly(ethylene terephthalate) (PET)bottles. In addition to issues of increased cost, environmental impact,hazards associated with wet surfaces, increased system complexity, andrisk of environmental stress cracking, the practice of dilutinglubricant solutions at the point of use gives an unsightly and uncleanappearance.

“Dry lubes” have been described in the past as a solution to thedisadvantages of dilute aqueous lubricants. A “dry lube” historicallyhas referred to a lubricant composition with less than 50% water thatwas applied to a container or a conveyor without dilution. Methods ofapplying conveyor lubricants without in line dilution are described, forexample, in U.S. Pat. Nos. 6,288,012; 6,427,826; 6,485,794; 6,495,494;6,509,302; 6,576,298; 6,673,753; 6,780,823; 6,806,240; 6,821,568; U.S.Patent Applications 2004/0029741A1 and 2005/0003973A1; and PCT PatentApplication 01/07544.

In spite of the advantages of “dry lubes” and many efforts to utilizethem, practice of conveyor lubricant methods which utilize lubricants ina neat form without dilution are not widely practiced and are generallynot practiced in connection with PET bottles that are prone to stresscracking. For practical application of “dry lube” technology with PETbottles, two features which have not been found together in the priorart must be provided simultaneously: acceptable PET compatibility of thelubricant composition and practical means of dispensing.

Practical dispensing of conveyor lubricants requires careful control andmaintenance of optimal coefficient of friction values between packageand conveyor surfaces, as expressed as a coefficient of friction,sliding force, slip value, frictional resistance or similar term.Generally, the objective for lubricant composition formulation anddispensing in prior art patents and published records is to produce thelowest possible coefficient of friction between conveyed packages andconveyor surfaces. In practice this does not result in effectiveconveying. In a practical implementation of a conveyor lubricationprogram, it is in fact insufficient to produce the lowest possiblecoefficient of friction between conveyed packages and conveyor surfaces.Over application of lubricant compositions and unacceptably lowcoefficient of friction between packages and the conveyor surface canresult in decreased system efficiency up to and including completeinability to transport packages. In the case of packages with height towidth ratios much greater than 1, such as bottles, an unacceptably lowcoefficient of friction may result in an excessive number of tipped andfallen bottles. It is preferred to maintain a proper value for thecoefficient of friction that is not necessarily the minimum possiblevalue. Within the same conveyor line, the optimum coefficient offriction is different at different locations on the track. For example,lower coefficient of friction values between packages and conveyorsurfaces may be required in faster moving portions of the conveyor suchas where packages are being conveyed at a high speed in single file orin transition areas where packages move from single file lines tocolumns that are several packages wide. Higher coefficient of frictionvalues between packages and conveyor surfaces may be required near theend of conveyor lines to provide sufficient back pressure and forwardmotive force where packages are finally urged into trays, boxes, cartonsor the like. It is highly desirable that the lubricant dispensing systembe able to provide different values for the coefficient of friction atdifferent locations on the same conveyor line without requiringdifferent concentrations of lubricant. The capability to providedifferent coefficient of friction values at different conveyor locationswith the same lubricant composition is especially important in the casethat the lubricant is not diluted with water at the point of use.Different coefficient of friction values at different conveyor locationsis necessarily provided by varying lubricant dispensing systemparameters such as the volume of lubricant composition dispensed perarea per time.

Several patents acknowledge a preference to minimize lubricant useamounts for reasons of cost. For example, U.S. Patent Application2004/0029741 states that “Dispensing equipment developed for dosing theliquid composition of the invention has been designed to apply theliquid directly to the surface of the conveyor belt. Since relativelyexpensive neat product is applied, this equipment has been developedsuch that any spillage of liquid material (e.g. by flowing under gravityaway from the treated surface or dripping down onto the floor) isavoided so as to minimize wastage of said liquid.” A dispensing devicerecommended in U.S. Patent Application 2004/0029741 is a so-called“flicker” non contact applicator. U.S. Pat. No. 6,382,524 pertains to a“flicker” applicator for applying lubricants which comprises acylindrical brush that is rotatably mounted in a frame and transferslubricant from a pick up roller to a conveyor surface by a “flickingaction.” U.S. Pat. No. 6,688,434 also states a preference to minimizelubricant use amounts for reasons of cost and waste. According to U.S.Pat. No. 6,688,434 “if too little lubricant composition is sprayed, itis expected that there will be insufficient lubricity between theconveyor and the items being transported on the conveyor. If too much ofthe lubricant composition is sprayed, it is expected that there will besome waste and increased cost.” U.S. Pat. No. 6,688,434 describes anelaborate dispensing apparatus in which gaseous pressure is used toevenly distribute lubricant through a system of high pressure lubricantlines, nozzles, nozzle valves, and spray valves and to actuateindividual spray valves. Other patents describe other lubricantdispensing approaches. For example, U.S. Pat. No. 6,102,161 describes adispensing device in which a liquid lubricant composition soaks a feltcloth which rests on a conveyor surface and is transferred to theconveyor by contact. U.S. Pat. No. 6,576,298 describes apparatus togenerate finely divided droplets or particulates of lubricants bycontacting a lubricant flow with an air flow. Dispensing systemsaccording to U.S. Pat. No. 6,576,298 describe separate subsystems forthe distribution of compressed air and lubricant composition throughoutthe conveyor system.

Although prior art patents describe equipment that is capable ofapplying conveyor lubricant compositions with reduced dripping andwaste, they do so with apparatus that are too complex and elaborate.Furthermore, prior art methods seek only to minimize use amounts oflubricant compositions and do not teach methods that are effective toprovide different values for the coefficient of friction at differentlocations.

It is against this background that the present invention has been made.

SUMMARY OF THE INVENTION

Surprisingly, it has been discovered that some silicone emulsions do notpromote stress cracking in PET containers while other silicone emulsionsactually promote stress cracking in silicone emulsions. This isunexpected because it has been thought that most silicone emulsions werevery similar. However, when various silicone emulsions were tested onPET bottles, it was observed that some silicone emulsions clearly causedbottle failure where others did not.

Specifically, it has been discovered, that silicone emulsions where thetriethanolamine salt of an alkyl benzene sulfonic acid (TEA ABSA) wherethe alkyl is a linear or branched unsubstituted alkyl group is part ofthe silicone emulsion promote stress cracking in PET. Triethanolaminesalts of alkyl benzene sulfonic acids are anionic surfactants sometimesincluded as emulsifiers in silicone emulsions.

Accordingly, the present invention is generally directed to a siliconeconveyor lubricant and methods of lubricating a conveyor using asilicone conveyor lubricant where the silicone emulsion does not promotestress cracking in PET containers. In some embodiments, the siliconeconveyor lubricant uses a silicone emulsion that does not contain TEAABSA compounds or includes TEA ABSA compounds in small amounts. In someembodiments, the silicone conveyor lubricant has less than 500 ppm ofTEA ABSA compounds. In some embodiments, the silicone conveyor lubricantis substantially free of TEA ABSA compounds. In some embodiments, thesilicone conveyor lubricant is substantially free of anionic surfactant.

In some embodiments, the silicone lubricants of present invention mayhave greater than 50% water. In some embodiments, the present inventionmay have less than 50% water. In some embodiments, the present inventioncan be applied by spraying using non-energized nozzles. In someembodiments, the present invention provides, in one aspect, a method forlubricating the passage of a container along a conveyor comprisingapplying a lubricant composition containing a water-miscible siliconematerial to at least a portion of the container contacting surface ofthe conveyor or to at least a portion of the conveyor-contacting surfaceof the container, wherein the concentration of triethanolamine salts ofalkyl benzene sulfonic acid (TEA ABSA) compounds in the composition isless than about 500 ppm.

In some embodiments, the present invention is directed to a siliconelubricant that is not diluted prior to applying it to a conveyor orcontainer surface. In some embodiments, the present invention isdirected to a method of applying an undiluted lubricant intermittently.In some embodiments, the present invention is directed to a “universal”lubricant that may be used with a variety of container and conveyormaterials.

In some embodiments, the present invention is directed to a method oflubricating an entire conveyor where the silicone lubricant is used on aconveyor but applied at different rates (i.e. quantity of lubricantdispensed per area per time) depending on the location on the conveyor.

In some embodiments, the lubricant mixture also comprises a watermiscible lubricant. In some embodiments, the water-miscible lubricant isselected from the group consisting of a phosphate ester, an amine, andan amine derivative. In some embodiments, the water-miscible lubricantis a traditional glass or metal lubricant.

DETAILED DESCRIPTION

Definitions

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the term “about” may include numbers thatare rounded to the nearest significant figure.

Weight percent, percent by weight, % by weight, wt %, and the like aresynonyms that refer to the concentration of a substance as the weight ofthat substance divided by the weight of the composition and multipliedby 100.

The recitation of numerical ranges by endpoints includes all numberssubsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3,3.80, 4 and 5).

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contentclearly dictates otherwise. Thus, for example, reference to acomposition containing “a compound” includes a mixture of two or morecompounds. As used in this specification and the appended claims, theterm “or” is generally employed in its sense including “and/or” unlessthe content clearly dictates otherwise.

Compositions

As previously discussed, the present invention is generally directed tosilicone lubricant compositions that contain a silicone emulsion thathas less than 500 ppm of TEA ABSA compounds. In some embodiments, thesilicone emulsion is free of TEA ABSA compounds, and in someembodiments, the silicone emulsion is free of anionic surfactants.Triethanolamine salts of alkyl benzene sulfonic acids includingtriethanolamine dodecyl benzene sulfonic acid (TEA DDBSA) are commonemulsifiers which provide excellent emulsion stability, resistance tocreaming, and freeze-thaw stability in silicone emulsions. However, inthe case of lubricant compositions and especially substantially aqueouslubricant composition which comprise silicone emulsions, TEA ABSAcompounds decrease the PET compatibility of the lubricant. Inparticular, silicone emulsion containing lubricant compositions with TEAABSA compound concentrations above about 500 ppm will cause relativelygreater risk of stress cracking. The reason that presence of TEA ABSAcompounds cause a loss of compatibility is unknown. The finding that PETcompatibility is reduced by the presence of TEA ABSA compounds isremarkable because TEA ABSA compounds in part and in whole have beenpatented numerous times as “stress crack inhibitors” for poly(alkyleneterephthalate) articles including carbonated beverage bottles.Hydrophilic substituted aromatic hydrocarbons with alkyl side chainsincluding alkyl benzene sulfonate salt compounds are claimed as “stresscrack inhibitors” for poly(alkylene terephthalate) polymers in U.S. Pat.No. 5,009,801. Amines having at least six carbon atoms includingtriethanolamine and mixtures of amines and alkyl substituted arylsulfonates are claimed as “stress crack inhibitors” for poly(alkyleneterephthalate) polymers including PET beverage bottles in U.S. Pat. No.5,073,280. According to U.S. Pat. No. 5,223,162, amines includingtriethanolamine are useful as additional stress crack inhibitors forpoly(alkylene terephthalate) articles in caustic aqueous bottle washingsolutions containing alkyl substituted aryl sulfonate compound primarystress crack inhibitors. In U.S. Patent Application 2004/0029741 A1, itis stated that “anionic surfactants may improve the PET compatibility ofa liquid composition containing a polyhydridic alcohol such asglycerine.” According to U.S. Patent Application 2004/0029741 A1,examples of suitable anionic surfactants include ammonium salts ofalkylbenzene sulfonates having from 10 to 18 carbon atoms in the alkylgroup.

Silicone emulsions include emulsions formed from silicone materials suchas methyl(dimethyl), higher alkyl and aryl silicones and functionalizedsilicones such as chlorosilanes, amino-, methoxy-, epoxy- andvinyl-substituted siloxanes, and silanols. Useful silicone emulsionscontain no triethanolamine salts of alkyl benzene sulfonic acid (TEAABSA) compounds or sufficiently small concentrations of TEA ABSAcompounds such that the concentration of TEA ABSA compounds in the finallubricant composition is less than about 500 ppm. Whether or not TEAABSA compounds are present, suitable silicone emulsions preferablycontain emulsifiers other than TEA ABSA compounds. Preferred emulsifiersused in the preparation of silicone emulsions include nonionicsurfactants such as linear and branched alkyl phenol ethoxylates, linearand branched primary alcohol ethoxylates, linear and branched secondaryalcohol ethoxylates, poly alkylene oxide modified polydimethylsiloxanes,sorbitan derivatives such as polyoxyethylene sorbitan mono oleate andsorbitan monolaurate; anionic surfactants such as sodium alkyl arylpolyether sulfonate compounds and sodium alkyl aryl sulfonate compounds;and cationic surfactants such as trimethyl ammonium salts. Examples ofpreferred emulsifiers for silicone emulsions include members of theSurfonic L series, Surfonic N series, Surfonic OP series, Ecoteric Tseries, and Nansa SS series from Huntsman Chemical, Houston Tex.;members of the Tergitol NP series, Triton X series, Tergitol TMN series,and Tergitol 15-S series from Dow Chemical Company, Midland Mich.;Tomadol surfactant products from Tomah3 Products, Inc., Milton, Wis.;members of the Arlacel and Tween series from Uniqema, New Castle Del.;members of the Silwet series from GE Silicones, Wilton N.Y.; members ofthe Abil series surfactants from Goldschmidt Personal Care, Hopewell,Va.; members of the Arquad series surfactants from Akzo Nobel Chemicals,Inc., Chicago Ill.; and equivalent products.

Suitable silicone emulsions made using preferred emulsifiers includeE2175 high viscosity polydimethylsiloxane (a 60% siloxane emulsioncommercially available from Lambent Technologies, Inc.), E2140polydimethylsiloxane (a 35% siloxane emulsion commercially availablefrom Lambent Technologies, Inc.), E2140 FG food grade intermediateviscosity polydimethylsiloxane (a 35% siloxane emulsion commerciallyavailable from Lambent Technologies, Inc.), Dow Corning HV600 Emulsion(a non-ionic 55% trimethylsilyl terminated polydimethylsiloxanedispersion available from Dow Corning), Dow Corning 1664 Emulsion (anon-ionic 50% trimethylsilyl terminated polydimethylsiloxane dispersionavailable from Dow Corning), Dow Corning 1101 (an anionic, 50% activeemulsion based on silanol terminated high viscosity polydimethylsiloxaneavailable from Dow Corning), Dow Corning 346 (a non-ionic, 60% activetrimethylsilyl terminated polydimethylsiloxane emulsion available fromDow Corning, Midland Mich.), GE SM 2068A (an anionic 35% silanolterminated polydimethylsiloxane dispersion available from GeneralElectric Silicones, Wilton N.Y.), GE SM 2128 (a non-ionic 35%trimethylsilyl terminated polydimethylsiloxane dispersion available fromGeneral Electric Silicones), GE SM 2135 (a non-ionic 50% trimethylsilylterminated polydimethylsiloxane dispersion available from GeneralElectric Silicones), GE SM 2138 (a non-ionic 60% silanol terminatedpolydimethylsiloxane dispersion available from General ElectricSilicones), GE SM 2140 (a non-ionic 50% trimethylsilyl terminatedpolydimethylsiloxane dispersion available from General ElectricSilicones), GE SM 2154 (a non-ionic 50% methylhexylisopropylbenzylsiloxane dispersion available from General Electric Silicones), GE SM2162 (a non-ionic 50% trimethylsilyl terminated polydimethylsiloxanedispersion available from General Electric Silicones), GE SM 2163 (anon-ionic 60% trimethylsilyl terminated polydimethylsiloxane dispersionavailable from General Electric Silicones), GE SM 2167 (a cationic 50%trimethylsilyl terminated polydimethylsiloxane dispersion available fromGeneral Electric Silicones), GE SM 2169 (a non-ionic 60% trimethylsilylterminated polydimethylsiloxane dispersion available from GeneralElectric Silicones), GE SM 2725 (an anionic 50% silanol terminatedpolydimethylsiloxane dispersion available from General ElectricSilicones), KM 901 (a non-ionic 50% trimethylsilyl terminatedpolydimethylsiloxane dispersion available from Shin-Etsu Silicones ofAmerica, Inc. Akron, Ohio), Fluid Emulsion E10 (a nonionic 38% siliconeemulsion available from Wacker silicones, Adrian, Mich.), Fluid EmulsionE1044 (a nonionic 39% silicone emulsion available from Wacker silicones,Adrian, Mich.), KM 902 (a non-ionic 50% trimethylsilyl terminatedpolydimethylsiloxane dispersion available from Shin-Etsu Silicones ofAmerica, Inc. Akron, Ohio), and equivalent products. Preferred siliconeemulsions typically contain from about 30 wt. % to about 70 wt. % water.Non-water-miscible silicone materials (e.g., non-water-soluble siliconefluids and non-water-dispersible silicone powders) can also be employedin the lubricant if combined with a suitable emulsifier (e.g., nonionic,anionic or cationic emulsifiers). Care should be taken to avoid the useof emulsifiers or other surfactants that promote environmental stresscracking in plastic containers.

Polydimethylsiloxane emulsions are preferred silicone materials.

In addition to the silicone emulsion, the lubricant composition cancontain additional functional ingredients if desired. For example, thecompositions can contain water miscible lubricants, hydrophilicdiluents, antimicrobial agents, stabilizing/coupling agents, detergentsand dispersing agents, anti-wear agents, viscosity modifiers,sequestrants, corrosion inhibitors, film forming materials, antioxidantsor antistatic agents. The amounts and types of such additionalcomponents will be apparent to those skilled in the art. Care should betaken to avoid the use of functional ingredients that might promoteenvironmental stress cracking in plastic containers when evaluated usingthe PET Stress Crack Test set out below.

Water-Miscible Lubricants

A variety of water-miscible lubricants can be employed in the lubricantcompositions, including hydroxy-containing compounds such as polyols(e.g., glycerol and propylene glycol); polyalkylene glycols (e.g., theCARBOWAX™ series of polyethylene and methoxypolyethylene glycols,commercially available from Union Carbide Corp.); linear copolymers ofethylene and propylene oxides (e.g., UCON™ 50-HB-100 water-solubleethylene oxide:propylene oxide copolymer, commercially available fromUnion Carbide Corp.); and sorbitan esters (e.g., TWEEN™ series 20, 40,60, 80 and 85 polyoxyethylene sorbitan monooleates and SPAN™ series 20,80, 83 and 85 sorbitan esters, commercially available from ICISurfactants). Other suitable water-miscible lubricants include phosphateesters, amines and their derivatives such as amine salts and fattyamines, and other commercially available water-miscible lubricants thatwill be familiar to those skilled in the art. Derivatives (e.g., partialesters or ethoxylates) of the above lubricants can also be employed.Examples of suitable phosphate ester lubricants include polyethylenephenol ether phosphate and those phosphate esters described in U.S. Pat.No. 6,667,283, which is incorporated by reference herein in itsentirety. Examples of suitable amine or amine derivative lubricantsinclude oleyl diamino propane, coco diamino propane, lauryl propyldiamine, dimethyl lauryl amine, PEG coco amine, alkyl C₁₂-C₁₄ oxy propyldiamine, and those amine compositions described in U.S. Pat. Nos.5,182,035 and 5,932,526, both of which are incorporated by referenceherein in their entirety. Preferably the water-miscible lubricantsinclude linear copolymers of ethylene and propylene oxides, fatty aminesalts and alcohol ethoxylates and derivatives thereof.

Hydrophilic Diluents

Suitable hydrophilic diluents include alcohols such as isopropylalcohol, polyols such as ethylene glycol and glycerine, ketones such asmethyl ethyl ketone, and cyclic ethers such as tetrahydrofuran. Ifhydrophilic diluents are used, care must be taken not to increase thelubricant composition viscosity to greater than about 40 centipoiseswhen measured using a Brookfield viscometer with an RV2 spindle at aspeed of 20 RPM.

Antimicrobial Agents Antimicrobial agents can also be added. Some usefulantimicrobial agents include disinfectants, antiseptics, andpreservatives. Some non-limiting examples include phenols includinghalo- and nitrophenols and substituted bisphenols such as4-hexylresorcinol, 2-benzyl-4-chlorophenol and2,4,4′-trichloro-2′-hydroxydiphenyl ether; organic and inorganic acidsand corresponding esters and salts such as dehydroacetic acid,peroxycarboxylic acids, peroxyacetic acid, peroxyoctanoic acid, methylp-hydroxy benzoic acid; cationic agents such as quaternary ammoniumcompounds; amine or amine salts such as oleyl diamino propane diacetate,coco diamino propane diacetate, lauryl propyl diamine diacetate,dimethyl lauryl ammonium acetate; isothiazolinone compounds such as2-methyl-4-isothiazolin-3-one and5-chloro-2-methyl-4-isothiazolin-3-one; phosphonium compounds such astetrakishydroxymethyl phosphonium sulphate (THPS), aldehydes such asglutaraldehyde, antimicrobial dyes such as acridines, triphenylmethanedyes and quinines; and halogens including iodine and chlorine compounds.The antimicrobial agents can be used in amounts to provide the desiredantimicrobial properties. In some examples, the amount can range from 0to about 20 wt.-% of the total composition.

Stabilizing/Coupling Agents

In a lubricant composition, stabilizing agents, or coupling agents canbe employed to keep the concentrate homogeneous, for example, under coldtemperature. Some of the ingredients may have the tendency to phaseseparate or form layers due to the high concentration. Many differenttypes of compounds can be used as stabilizers. Examples are isopropylalcohol, ethanol, urea, octane sulfonate, and glycols such as hexyleneglycol, propylene glycol and the like. The stabilizing/coupling agentscan be used in an amount to give desired results. This amount can range,for example, from about 0 to about 30 wt.-% of the total composition.

Detergents/Dispersing Agents

Detergents of dispersing agents may also be added. Some examples ofdetergents and dispersants include alkyl benzene sulfonic acid,alkylphosphonic acids, and their calcium, sodium, and magnesium salts,polybutenylsuccinic acid derivatives, silicone surfactants,fluorosurfactants, and molecules containing polar groups attached to anoil-solubilizing aliphatic hydrocarbon chain.

Some examples of suitable dispersing agents include alkoxylated fattyalkyl monoamines and diamines such as coco bis (2-hydroxyethyl)amine,polyoxyethylene (5)-coco amine, polyoxyethylene(15)coco amine, tallowbis(-2hydroxyethyl)amine, polyoxyethylene(15)amine,polyoxyethylene(5)oleyl amine and the like.

The detergent and/or dispersants can be used in an amount to givedesired results. This amount can range, for example, from about 0 toabout 30 wt.-% of the total composition.

Anti-wear Agents

Anti-wear agents can also be added. Some examples of anti-wear agentsinclude zinc dialkyl dithiophosphates, tricresyl phosphate, and alkyland aryl disulfides and polysulfides. The anti-wear and/or extremepressure agents are used in amounts to give the desired results. Thisamount can range, for example, from 0 to about 20 wt.-% of the totalcomposition.

Corrosion Inhibitors

Useful corrosion inhibitors include polycarboxylic acids such as shortchain carboxylic diacids, triacids, as well as phosphate esters andcombinations thereof. Useful phosphate esters include alkyl phosphateesters, monoalkyl aryl phosphate esters, dialkyl aryl phosphate esters,trialkyl aryl phosphate esters, and mixtures thereof such as Emphos PS236 commercially available from Witco Chemical Company. Other usefulcorrosion inhibitors include the triazoles, such as benzotriazole,tolyltriazole and mercaptobenzothiazole, and in combinations withphosphonates such as 1-hydroxyethylidene-1, 1-diphosphonic acid, andsurfactants such as oleic acid diethanolamide and sodiumcocoamphohydroxy propyl sulfonate, and the like. Useful corrosioninhibitors include polycarboxylic acids such as dicarboxylic acids. Theacids which are preferred include adipic, glutaric, succinic, andmixtures thereof. The most preferred is a mixture of adipic, glutaric,and succinic acid, which is a raw material sold by BASF under the nameSOKALAN™ DCS.

The lubricant composition is preferably a liquid at the time ofapplication. The lubricant composition preferably has a viscosity thatwill permit it to be pumped and readily applied to a conveyor orcontainers, and that will facilitate rapid film formation whether or notthe conveyor is in motion. The lubricant composition can be formulatedso that it exhibits shear thinning or other pseudo-plastic behavior,manifested by a higher viscosity (e.g., non-dripping behavior) when atrest, and a much lower viscosity when subjected to shear stresses suchas those provided by pumping and spraying. However, it is preferablethat whether shear thinning or not, the lubricant composition has a lowviscosity at low shear rates. In the case of applying a lubricantcomposition intermittently, there is difficulty in achieving sufficientpressure throughout the lubricant distribution system. The difficulty isrelated to the viscosity of the lubricant composition and the distancebetween the lubricant pressure source and the extremities of thelubricant distribution system. For example, as distances in thelubricant distribution system increase, it is difficult to provide arapid increase in pressure at the dispensing nozzles that triggers thespray pattern and a rapid decrease in pressure that shuts off flow. Thetransmission of pressure in the lubricant line from the lubricant sourceto the spray nozzle is impeded by high lubricant viscosity, andspecifically high lubricant viscosity at low shear rates. Prior artsolutions to this problem were typically mechanical in nature andincluded the use of high pressures and elaborate dispensing apparatus.

Low lubricant viscosity is important to achieve acceptable spraypatterns from non-energized nozzles at pressures less than 80 psi.Energized nozzles refer to nozzles where the lubricant stream is brokeninto a spray of fine droplets by the use of energy, which may includehigh pressures, compressed air, or sonication to deliver the lubricant.An example of a preferable non-energized nozzle is a Low Flow FloodJet1/8K-SS.25 nozzle (available from Spraying Systems, Wheaton Ill.).Preferably the lubricant dispensing system operates at a pressure lessthan about 60 psi. Higher pressures pose a greater problem of leakage,particularly in the case where plastic tubing is used for the lubricantdistribution lines. It also requires additional equipment systemcapabilities to operate with higher pressures, for example high pressurelubricant lines, spray valves, and lubricant venting lines. For properdispensing with non-energized nozzles such as Low Flow FloodJet1/8K-SS.25 nozzles at pressures less than 60 psi, it is preferred thatthe lubricant viscosity be less than about 40 centipoises. Preferredlubricants have a viscosity less than about 40 centipoises, less than 25centipoises, and less than 15 centipoises when measured using aBrookfield viscometer with an RV2 spindle at a speed of 20 RPM.Preferred lubricant dispensing system pressures are 5-80 psi, 20-60 psi,and 25-50 psi.

Preferred amounts for the silicone material, water miscible lubricantand water or hydrophilic diluent are about 0.0015% to about 50 wt. % ofthe silicone material (exclusive of any water or other hydrophilicdiluent and emulsifier that may be present if the silicone material is,for example, a silicone emulsion), about 0 to about 20 wt. % of thewater miscible lubricant, and about 50 to about 99.999 wt. % of water orhydrophilic diluent. More preferably, the lubricant composition containsabout 0.0075 to about 20 wt. % of the silicone material, about 0.0010%to about 15 wt. % of the water miscible lubricant, and about 65 to about99.99 wt. % of water or hydrophilic diluent. Most preferably, thelubricant composition contains about 0.045% to about 7 wt. % of thesilicone material, about 0.006 to about 10 wt. % of the hydrophiliclubricant, and about 85 to about 99.95 wt. % of water or hydrophilicdiluent.

Preferred lubricant compositions are substantially aqueous, that is, themajor constituent is water. The use of water as a vehicle for lubricantcompositions is capable to provide viscosity that is sufficiently low,i.e. less than about 40 centipoises when measured using a Brookfieldviscometer with an RV2 spindle at a speed of 20 RPM, so as to enabledispensing by simple lubricant distribution systems operating at lowpressures using non-energized nozzles. In the case that lubricantcompositions are substantially aqueous, care must be taken to insure thePET compatibility of the composition. By “compatible with PET” or “PETcompatibility”, it is meant that PET bottles filled with a carbonatedliquid will show a relatively lower failure rate when stored in a hotand humid environment. Although using lubricants that are not dilutedwith water in the lubricant distribution system eliminates the problemof compatibility loss arising from alkalinity in the water used todilute the lubricant (i.e. the water coming out at a filling orpackaging plant), the nature of the emulsifiers present in the lubricantcomposition becomes critical because they are present in the compositionat higher concentrations. Accordingly, the presence of emulsifiers,including emulsifiers which are claimed to be “stress crack inhibitors”in lubricant and bottle washing compositions can cause sufficientreduction to the PET compatibility of silicone emulsion based lubricantsso that such compositions are unacceptable for use on non-returnable PETcarbonated soft drink bottles.

The PET compatibility of lubricant compositions may also be improved byincluding a stoichiometric amount of an acid. Lubricant compositionscomprising a stoichiometric amount of an acid and having improvedcompatibility with PET are disclosed in patent application Ser. No.11/233,568, titled SILICONE CONVEYOR LUBRICANT WITH STOICHIOMETRICAMOUNT OF AN ACID, the entire disclosure of which is incorporated hereinby reference in its entirety.

Preferred lubricant compositions may also contain a wetting agent.Lubricant compositions comprising a wetting agent and having improvedcompatibility with PET are disclosed in patent application Ser. No.11/233,596, titled SILICONE LUBRICANT WITH GOOD WETTING ON PET SURFACES,the entire disclosure of which is incorporated herein by reference inits entirety. Care should be taken to avoid the use of wetting agentsthat might promote environmental stress cracking in plastic containerswhen evaluated using the PET Stress Crack Test set out below.

For applications involving plastic containers, the lubricantcompositions preferably have a total alkalinity equivalent to less thanabout 100 ppm CaCO₃, more preferably less than about 50 ppm CaCO₃, andmost preferably less than about 30 ppm CaCO₃, as measured in accordancewith Standard Methods for the Examination of Water and Wastewater,18^(th) Edition, Section 2320, Alkalinity.

A variety of kinds of conveyors and conveyor parts can be coated withthe lubricant composition. Parts of the conveyor that support or guideor move the containers and thus are preferably coated with the lubricantcomposition include belts, chains, gates, chutes, sensors, and rampshaving surfaces made of fabrics, metals, plastics, composites, orcombinations of these materials.

The lubricant composition can also be applied to a wide variety ofcontainers including beverage containers; food containers; household orcommercial cleaning product containers; and containers for oils,antifreeze or other industrial fluids. The containers can be made of awide variety of materials including glasses; plastics (e.g., polyolefinssuch as polyethylene and polypropylene; polystyrenes; polyesters such asPET and polyethylene naphthalate (PEN); polyamides, polycarbonates; andmixtures or copolymers thereof); metals (e.g., aluminum, tin or steel);papers (e.g., untreated, treated, waxed or other coated papers);ceramics; and laminates or composites of two or more of these materials(e.g., laminates of PET, PEN or mixtures thereof with another plasticmaterial). The containers can have a variety of sizes and forms,including cartons (e.g., waxed cartons or TETRAPAK™ boxes), cans,bottles and the like. The lubricant composition preferably contacts onlyparts of the container that will come into contact with the conveyor orwith other containers.

Dispensing Equipment

Preferred dispensing equipment for practice of the present inventionincludes spraying apparatus that comprises spray nozzles that arenon-energized, i.e. they provide a fine lubricant spray at relativelylow flow rates (preferably less than about 7.5 gallons/hour at pressuresless than about 60 psi) without requiring applied energy (for examplehigh pressure, compressed air, or sonication) to break up the lubricantflow into small droplets. The spray dispensing system operates atrelatively lower pressure (preferably less than about 60 psi) and doesnot comprise either a high pressure lubricant line or a lubricantventing line. Useful droplet sizes for the lubricant spray are fromabout 100 to about 5000 microns, preferably about 100 to about 500microns.

Preferred nozzles for the practice of the current invention are smallcapacity spray nozzles which distribute the liquid lubricant as a solid(full) cone, hollow cone, flat fan or sheet-type of spray at pressuresless than about 60 psi. Particularly preferred nozzles are flat spraynozzles with tapering edges which are useful in establishing uniformspray distribution from overlapping spray patterns between adjacentsprays on a multiple nozzle header. Flat spray nozzles useful in thepractice of the current invention include elliptical orifice nozzles anddeflector nozzles. In the elliptical orifice design, the axis of thespray pattern is a continuation of the axis of the inlet pipeconnection. In the deflector design, the deflection surface diverts thespray pattern away from the axis of the inlet pipe connection. Usefulflat spray nozzles include FloodJet and VeeJet Small Capacity Wide SprayAngle nozzles (available from Spraying Systems, Wheaton, Ill.), FF ExtraWide Angle and NF Standard Fan nozzles (available from Bete Fog Nozzle,Inc., Greenfield, Mass.), and Flat Spray Standard nozzles (availablefrom Allspray, Inc., Carol Stream, Ill.). A particularly preferreddeflector flat spray nozzle is the Low Flow FloodJet 1/8K-SS.25 nozzleavailable from Spraying Systems, Wheaton Ill. Useful cone spray nozzlesinclude UniJet Small Capacity Standard Spray nozzles (available fromSpraying Systems, Wheaton, Ill.), WT Right Angle Hollow Cone nozzles(available from Bete Fog Nozzle, Inc., Greenfield, Mass.), and HollowCone Standard nozzles (available from Allspray, Inc., Carol Stream,Ill.). A particularly preferred cone spray nozzle is the UniJetTXVS-1nozzle available from Spraying Systems, Wheaton Ill.

Dispensing apparatus for practice of the present invention includesmeans to provide lubricant compositions to nozzles under low to moderatepressures, less than about 60 psi. One possible means is to pressurizethe lubricant source. Preferred dispensing equipment includes means topressurize the lubricant composition in line by pumping. Therequirements for a pump are modest and can be met by a variety of pumpdesigns including diaphragm pumps, peristaltic pumps, and valvelessrotating reciprocating piston metering pumps. Particularly preferredpumps start and stop automatically when a discharge valve downstream ofthe pump is opened and closed. In this way, the pump is not operatingduring non-application periods. Examples of pumps that start and stopautomatically include positive displacement diaphragm pumps withbuilt-in pressure switches that automatically start and stop pumpinginstantaneously when the discharge valve is opened. An example includesa Flowjet 2100 pump available from Flowjet, a division of IITIndustries, Foothill Ranch, Calif. Other examples of pumps that startand stop automatically are positive displacement reciprocating doublediaphragm pumps such as the Wilden PI plastic pump available from WildenPump & Engineering, LLC,Grand Terrace, Calif. and pneumatic singlediaphragm pumps such as the Yamada NDP-5 pump available from YamadaAmerica, West Chicago Ill. Pumps which do not automatically start andstop upon action of a downstream discharge valve may advantageously beused with a controller that actuates both the downstream discharge valveand the pump.

The present invention provides several advantages over the prior art.First, the lubricant compositions have improved PET compatibility due tothe selection of PET compatible silicone emulsions. Additionally, insome embodiments, if sufficient water is included in the lubricantcomposition, the composition can be applied undiluted with simpleapplication equipment (i.e. non-energized nozzles). Applying “neat” orundiluted lubricant compositions can provide drier lubrication of theconveyors and containers, a cleaner and drier conveyor line and workingarea, and reduced lubricant usage, thereby reducing waste, cleanup anddisposal problems. Further, by adding water to the composition and notrequiring dilution upon application, problems created by dilution errorsand issues with quality of on site water (i.e. microorganisms that canreduce system cleanliness and alkalinity which can lead to environmentalstress cracking) are avoided. Intermittent application of the lubricantcomposition can provide the advantages of reduced lubricant usage,reduced cost, and decreased frequency that the lubricant containers haveto be switched.

Methods of Application

The lubricant coating can be applied in a constant or intermittentfashion. Preferably, the lubricant coating is applied in an intermittentfashion in order to minimize the amount of applied lubricantcomposition. It has been discovered that the present invention may beapplied intermittently and maintain an optimum and sufficiently lowcoefficient of friction in between applications. Specifically, thepresent invention may be applied for a period of time and then notapplied for at least 15 minutes, at least 30 minutes, or at least 120minutes or longer. The application period may be long enough to spreadthe composition over the conveyor belt (i.e. one revolution of theconveyor belt). During the application period, the actual applicationmay be continuous, i.e. lubricant is applied to the entire conveyor, orintermittent, i.e. lubricant is applied in bands and the containersspread the lubricant around. The lubricant is preferably applied to theconveyor surface at a location that is not populated by packages orcontainers. For example, it is preferable to apply the lubricant sprayupstream of the package or container flow or on the inverted conveyorsurface moving underneath and upstream of the container or package.

In some embodiments, the ratio of non-application time to applicationtime may be 5:1, 30:1, 180:1, and 1000:1 where the lubricant maintainsan optimal and low coefficient of friction in between lubricantapplications.

Particularly preferred lubricant compositions used in the inventioncontain greater than about 50%, greater than 65%, and greater than 85%of water or a hydrophilic diluent, as a component or components in thelubricant composition as sold or added just prior to use. The lubricantcompositions may contain a silicone material concentration of 0.0015% to60%, 0.0075% to 20%, and 0.045% to 7%. The lubricant compositions do notrequire in-line dilution with significant amounts of water, that is, itcan be applied undiluted or with relatively modest dilution, e.g., at awater:lubricant ratio of about 1:1, 5:1, or 30:1. Nozzles useful in thepractice of the current invention are non-energized and generate a finelubricant spray at low to moderate pressures between 5 psi and 80 psi,preferably between 20 psi and 60 psi, and have preferably between 30 psiand 50 psi, and deliver between 0.1 gallons/hour and 10 gallons/hour,preferably between 0.25 gallons/hour and 7.5 gallons/hour and morepreferably between 0.5 and 5.0 gallons/hour.

In some embodiments, a feedback loop may be used to determine when thecoefficient of friction reaches an unacceptably high level. The feedbackloop may trigger the lubricant composition to turn on for a period oftime and then optionally turn the lubricant composition off when thecoefficient of friction returns to an acceptable level.

The present invention is applied in such a way as to provide anacceptable coefficient of friction between the container and theconveyor. In preferred embodiments of the present invention, thecoefficient of friction (COF) has different values at differentlocations on the conveyor line. Proper determination of the coefficientof friction requires that any gravitational component be resolved andsubtracted from the force required to keep bottles stationary on amoving track in the case the conveyor track has a tilt perpendicular tothe direction of travel. In the case that the conveyor track is tilted,the frictional force is equal to cosθ times the measured force, where θis the angle between the direction of travel parallel to the horizon andthe direction of force measurement. The coefficient of friction at anypoint on the track should be averaged over at least one lubricantapplication/lubricant non application cycle. By average coefficient offriction it is meant the coefficient of friction averaged over one cycleof lubricant application/lubricant non-application. Preferredcoefficient of friction values for the present invention when measuredas discussed above range from about 0.05 to about 0.25. In preferredembodiments of the present invention, the ratio of the coefficient offriction at one portion of the conveyor surface to a second portion ofthe conveyor surface is greater than 1.05:1.00, greater than 1.10:1.00,and greater than 1.15:1.00.

The methods of the present invention provide a thin layer of lubricantat the interface between package and conveyor surfaces. The lubricantlayer may be substantially contiguous or may be discontinuous. Theaverage lubricant coating should be appropriately thick to provide thedesired degree of lubrication. The average lubricant coating thicknesspreferably is maintained at at least about 0.00001 mm, more preferablyabout 0.0001 to about 2 mm, and most preferably about 0.005 to about 0.5mm.

The lubricant compositions can if desired be evaluated using a SprayTest, a Viscosity Test, a Short Track Conveyor Test, and a PET StressCrack Test.

Spray Test

The spray test evaluates the capability of lubricant formulations to bedispensed using a non-energized nozzle. According to this test, the testlubricant solution is supplied to a Low Flow FloodJet 1/8K-SS.25 nozzle(available from Spraying Systems, Wheaton Ill.) through a Yamada NDP-5pump which is pressurized by compressed air. The hydrostatic pressure ofthe lubricant at the nozzle was varied by adjusting the pressure in theair line pressurizing the Yamada NDP-5 pump, and measured using a gaugenext to the nozzle. Using this apparatus, the spray angle of lubricantsolutions was determined when the pressure at the nozzle was 40 psi to110 psi.

Viscosity Test

The lubricant composition viscosity was measured using a Brookfieldviscometer with an RV2 spindle at a speed of 20 RPM.

Short Track Conveyor Test

A conveyor system employing two motor-driven REXNORD™ LF polyacetalthermoplastic conveyor belts 19 cm wide by 6.1 meter long was operatedat a belt speed of 30.48 meters/minute. A thin, even coat of thelubricant composition was dispensed to the surface of the belt using aLow Flow FloodJet 1/8K-SS.25 nozzle (available from Spraying Systems,Wheaton Ill.) fed by a Yamada NDP-5 pneumatic single diaphragm pump(available from Yamada America, Inc., West Chicago Ill.) at a deliverypressure of 40 psi for a time of 15 seconds. Four 20 ounce filled PETbeverage bottles were lassoed, placed on the conveyor belt and connectedto a stationary strain gauge. The force exerted on the strain gaugeduring belt operation was recorded using a computer. Following thedispensing of the lubricant composition, the belt was allowed to run for90 minutes during which time the drag force acting on the four bottleswas collected. The coefficient of friction (COF) was calculated bydividing the drag force (F) by the weight of the lasso and four 20 ouncefilled PET beverage bottles (W): COF=F/W. After 90 minutes withoutapplication, the cycle of dispensing lubricant for 15 seconds and notdispensing lubricant for 90 minutes was repeated two more times, usingfour new 20 ounce filled PET beverage bottles for each cycle. The COFbetween the bottles and conveyor at the end of the third 90 minuteperiod of not dispensing lubricant was recorded.

Pet Stress Crack Test

Compatibility of lubricant compositions with PET beverage bottles wasdetermined by charging bottles with carbonated water, contacting withlubricant composition, storing at elevated temperatures and humidity fora period of 28 days, and counting the number of bottles that eitherburst or leaked through cracks in the base portion of the bottle.Standard twenty ounce “Contour” bottles (available from SoutheasternContainer, Enka N.C.) were charged successively with 557 g of chilledwater at 0 to 5 C, 10.6 g of sodium bicarbonate, and 17.1 mL of 50%aqueous solution of citric acid. Immediately after addition of thecitric acid solution, the charged bottle was capped and the torque onthe bottle cap adjusted to 16 in-lb, and then the bottle was rinsed withdeionized water and stored at ambient conditions (20-25 C) overnight.Twenty four bottles thus charged were dipped in lubricant workingsolution up to the seam which separates the base and sidewall portionsof the bottle and swirled for approximately five seconds, then placed ina standard bus pan (part number 4034039, available from Sysco, HoustonTex.) lined with a polyethylene bag. Additional lubricant workingsolution was not poured into the bus pan so that the total amount oflubricant solution in the pan was that carried into the pan on thebottles. For each lubricant evaluated, a total of 48 to 96 bottles weretested. Immediately after placing bottles and lubricant into bus pans,the bus pans were removed to a humidity chamber under conditions of 100Fand 85% relative humidity. Bins were checked on a daily basis and numberof failed bottles was recorded. At the end of 28 days, the amount ofcrazing on the base region of bottles that did not fail during humiditytesting was evaluated. A visual crazing score was given to bottles where0=no crazing is evident, the bottle base remains clear; and10=pronounced crazing to the extent that the base has become opaque.

EXAMPLES

The invention can be better understood by reviewing the followingexamples. The examples are for illustration purposes only, and do notlimit the scope of the invention.

Comparative Example A

Lubricant Composition from U.S. Pat. No. 6,495,494

A lubricant composition was prepared according to EXAMPLE 2 of U.S. Pat.No. 6,495,494. Dow Corning Corporation HV490 silicone emulsion (2.1parts), 96 wt. % glycerol solution (77.2 parts) and deionized water(20.7 parts) were combined with stirring until a uniform mixture wasobtained. The viscosity of the lubricant solution measured with aBrookfield viscometer using an RV2 spindle at 20 rpm was determined tobe 42 centipoises. The lubricant composition was subjected to thespraying test as described above. With a nozzle pressure of 40 psi, thelubricant dispensed from the Low Flow FloodJet 1/8K-SS.25 nozzle in astream, not a fan spray and the lubricant spray angle was less than 10degrees. When the pressure at the nozzle was increased to up to 110 psi,the lubricant continued to dispense in a stream and did not dispense ina fan spray pattern. What this comparative example shows is that thelubricant composition of EXAMPLE 2 of U.S. Pat. No. 6,495,494 does notgive a useful spray pattern when dispensed with a Low Flow FloodJet1/8K-SS.25 nozzle at 40-110 psi pressure.

Comparative Example B

(Dry Silicone Lubricant which Contains Triethanolamine Dodecyl BenzeneSulfonate, a Triethanolamine Salt of an Alkyl Benzene Sulfonic AcidCompound)

In a first step, a fatty amine solution was prepared by adding 7.5 g ofDuomeen OL (available from Akzo Chemicals, Inc. Chicago Ill.), 3.0 g ofDuomeen CD (available from Akzo Chemicals, Inc. Chicago Ill.), 4.5 g ofGenamin LA 302D (available from Clariant Corporation, Mount Holly,N.C.), 3.0 g of Chemeen C-12G surfactant (available from Chemax, Inc.,Greenville, S.C.), 6.4 g of glacial acetic acid, 9.0 g Surfonic TDA-9surfactant (available from Huntsman Corporation, Houston, Tex.), and 1.8g of 45% aqueous potassium hydroxide to 63.4 g of softened water. Alubricant solution was prepared which contained 2.0 g of fatty aminesolution, 4.0 g of Dow Corning HV-490 silicone emulsion (available fromDow Corning Corporation, Midland, Mich.) and 194 g of deionized water.The lubricant solution was tested for PET compatibility as describedabove. After 20 days of storage under conditions of 100F and 85%relative humidity, 14 of 96 bottles (15%) had failed. The visual crazingscore for the unfailed bottles in this test was 6.7. The content of TEADDBSA in the Dow Corning HV-490 emulsion was determined by anionelectrode titration to be 8.7% and the concentration of TEA DDBSA in thelubricant solution was 1740 ppm. What this comparative example shows isthat a substantially aqueous dry silicone lubricant composition whichcontains 1740 ppm of TEA DDBSA has an unacceptable rate of failure inthe PET compatibility test.

Comparative Example C

(Dry Silicone Lubricant which Contains Triethanolamine Dodecyl BenzeneSulfonate)

A lubricant solution was prepared which contained 2.0 g of the fattyamine solution of Comparative Example B, 4.0 g of Lambent E-2140 FGsilicone emulsion, 5.8 g of a 10% solution of Bio Soft N-300 surfactantsolution (Bio Soft N-300 is a 60% aqueous solution of TEA DDBSAavailable from Stepan, Northfield Ill.), and 188 g of softened water.The lubricant solution contained 1740 ppm TEA DDBSA by formulation. Thelubricant solution was tested for PET compatibility as described above.After 28 days of storage under conditions of 100F and 85% relativehumidity, 13 of 96 bottles (14%) had failed. The visual crazing scorefor the unfailed bottles in this test was 8.0. What this comparativeexample shows is that a substantially aqueous dry silicone lubricantcomposition which contains 1740 ppm of TEA DDBSA has an unacceptablerate of failure in the PET compatibility test.

Example 1

(Dry Silicone Lubricant which does not Contain Triethanolamine DodecylBenzene Sulfonate)

A lubricant solution was prepared which contained 2.0 g of the fattyamine solution of Comparative Example B, 4.0 g of Lambent E-2140 FGsilicone emulsion (available from Lambent Technologies Corporation,Fernandina Beach, Fla.) and 194 g of softened water. The viscosity ofthe lubricant solution measured with a Brookfield viscometer using anRV2 spindle at 20 rpm was determined to be 10 centipoises. The lubricantsolution was subjected to the spraying test described above. With anozzle pressure of 40 psi, the lubricant spray angle was 110 degrees.When tested for lubricity using the Short Track Conveyor Test describedabove, the COF between the bottles and conveyor at the end of the third90 minute period of not dispensing lubricant was 0.125. The lubricantsolution was tested for PET compatibility as described above. After 28days of storage under conditions of 100F and 85% relative humidity, 2 of48 bottles (4%) had failed. The visual crazing score for the unfailedbottles in this test was 5.9. Lambent E-2140 FG silicone emulsion doesnot contain TEA DDBSA. What this example shows is that a substantiallyaqueous dry silicone lubricant composition which does not contain TEADDBSA provides a lower failure rate in the PET compatibility testrelative to a silicone lubricant which contains TEA DDBSA.

Example 2

(Dry Silicone Lubricant which Contains less than 40 ppm TriethanolamineDodecyl Benzene Sulfonate)

A lubricant composition was prepared which contained 2.0 g of the fattyamine solution of Comparative Example B, 2.6 g of Dow Corning HV 600silicone emulsion (available from Dow Corning Corporation, Midland,Mich.) and 195 g of deionized water. The lubricant composition wastested for lubricity using the Short Track Conveyor Test describedabove, except that the third period of not dispensing lubricant was 60minutes instead of 90. The COF between the bottles and conveyor at theend of the third (60 minute) period of not dispensing lubricant was0.125. The lubricant solution was tested for PET compatibility asdescribed above. After 28 days of storage under conditions of 100F and85% relative humidity, 0 of 96 bottles (0%) had failed. The visualcrazing score for the unfailed bottles in this test was 5.1. Theconcentration of TEA DDBSA in Dow Corning HV 600 measured by the anionelectrode titration method is less than about 0.3%. What this exampleshows is that a substantially aqueous dry silicone lubricant compositionwhich contains less than about 40 ppm TEA DDBSA provides a lower failurerate in the PET compatibility test relative to a silicone lubricantwhich contains 1740 ppm TEA DDBSA.

Example 3

(Dry Silicone Lubricant which Contains less than 30 ppm TriethanolamineDodecyl Benzene Sulfonate)

A lubricant solution was prepared which contained 2.0 g of the fattyamine solution of Comparative Example B, 2.8 g of Dow Corning 1664silicone emulsion (available from Dow Corning Corporation, Midland,Mich.) and 195 g of deionized water. The lubricant solution was testedfor PET compatibility as described above. After 28 days of storage underconditions of 100F and 85% relative humidity, 0 of 96 bottles (0%) hadfailed. The visual crazing score for the unfailed bottles in this testwas 5.2. The concentration of TEA DDBSA in Dow Corning 1664 siliconeemulsion measured by the anion electrode titration method is less thanabout 0.2%. What this example shows is that a substantially aqueous drysilicone lubricant composition which contains less than 30 ppm TEA DDBSAprovides a lower failure rate in the PET compatibility test relative toa silicone lubricant which contains 1740 ppm TEA DDBSA.

Example 4

(Dry Silicone Lubricant which Contains less than 30 ppm TriethanolamineDodecyl Benzene Sulfonate)

A lubricant solution was prepared which contained 2.0 g of the fattyamine solution of Comparative Example B, 2.3 g of GE Silicones SM2169silicone emulsion (available from GE Silicones, Wilton, Conn.) and 196 gof deionized water. The lubricant solution was tested for PETcompatibility as described above. After 26 days of storage underconditions of 100F and 85% relative humidity, 0 of 96 bottles (0%) hadfailed. The visual crazing score for the unfailed bottles in this testwas 7.2. The concentration of TEA DDBSA in GE Silicones SM2169 siliconeemulsion measured by the anion electrode titration method is less thanabout 0.2%. What this example shows is that a substantially aqueous drysilicone lubricant composition which contains less than 30 ppm TEA DDBSAprovides a lower failure rate in the PET compatibility test relative toa silicone lubricant which contains 1740 ppm TEA DDBSA.

Example 5

(Dry Silicone Lubricant which Contains 190 ppm of TriethanolamineDodecyl Benzene Sulfonate)

A lubricant solution was prepared which contained 2.0 g of the fattyamine solution of Comparative Example B, 2.8 g of Dow Corning 1101silicone emulsion (available from Dow Corning Corporation, Midland,Mich.) and 195 g of deionized water. The lubricant solution was testedfor PET compatibility as described above. After 28 days of storage underconditions of 100F and 85% relative humidity, 1 of 72 bottles (1%) hadfailed. The visual crazing score for the unfailed bottles in this testwas 6.1. Dow Corning 1101 silicone emulsion is described as ananionic-nonionic silicone emulsion that contains TEA DDBSA. Theconcentration of TEA DDBSA in Dow Corning 1101 silicone emulsion wasdetermined to be 1.3% by the anion electrode titration method. Theconcentration of TEA DDBSA in the lubricant composition was 190 ppm.What this example shows is that a substantially aqueous dry siliconelubricant composition that contains 190 ppm TEA DDBSA provides a lowerfailure rate in the PET compatibility test relative to a siliconelubricant which contains 1740 ppm TEA DDBSA.

Comparative Example D

(Dry Silicone Lubricant which Contains Triethanolamine Dodecyl BenzeneSulfonate)

A lubricant solution was prepared which contained 4.0 g of LambentE-2140 FG silicone emulsion, 5.8 g of a 10% solution of Bio Soft N-300surfactant solution (Bio Soft N-300 is a 60% aqueous solution of TEADDBSA available from Stepan, Northfield Ill.), and 190 g of softenedwater. The lubricant solution contained 1740 ppm TEA DDBSA byformulation. The lubricant solution was tested for PET compatibility asdescribed above. After 28 days of storage under conditions of 100F and85% relative humidity, 9 of 96 bottles (9%) had failed. The visualcrazing score for the unfailed bottles in this test was 8.0. What thiscomparative example shows is that a substantially aqueous dry siliconelubricant composition which contains 1740 ppm of TEA DDBSA has anunacceptable rate of failure in the PET compatibility test.

Example 6

(Dry Silicone Lubricant which does not Contain Triethanolamine DodecylBenzene Sulfonate)

In a first step, a fatty amine solution was prepared by adding 10.0 g ofDuomeen OL (available from Akzo Chemicals, Inc. Chicago Ill.), and 3.6 gof glacial acetic acid to 86.4 g of deionized water. A lubricantsolution was prepared which contained 50.0 g of the fatty aminesolution, 50.0 g of Lambent E-2140 FG silicone emulsion, and 5.0 g ofSurfonic L24-7 surfactant (available from Huntsman LLC, Houston, Tex.)and 895 g of deionized water. The lubricant solution was tested for PETcompatibility as described above. After 28 days of storage underconditions of 100F and 85% relative humidity, 0 of 48 bottles (0%) hadfailed. Lambent E-2140 FG silicone emulsion does not contain TEA DDBSA.What this example shows is that a substantially aqueous dry siliconelubricant composition which does not contain TEA DDBSA provides a lowerfailure rate in the PET compatibility test relative to a siliconelubricant which contains TEA DDBSA.

The foregoing summary, detailed description, and examples provide asound basis for understanding the invention, and some specific exampleembodiments of the invention. Since the invention can comprise a varietyof embodiments, the above information is not intended to be limiting.The invention resides in the claims.

1. A method for lubricating the passage of a container along a conveyorcomprising applying a lubricant composition through non-energizednozzles to at least a portion of the container-contacting surface of theconveyor or at least a portion of the conveyor-contacting surface of thecontainer, the lubricant composition comprising a silicone emulsion,wherein the lubricant composition contains less than about 500 ppm oftriethanolamine salts of alkyl benzene sulfonic acid compounds.
 2. Themethod of claim 1, wherein the silicone emulsion includes emulsifiersother than triethanolamine salts of alkyl benzene sulfonic acidcompounds.
 3. The method of claim 1, wherein the silicone emulsionincludes emulsifiers selected from the group of linear alkyl phenolethoxylates, branched alkyl phenol ethoxylates, linear primary alcoholethoxylates, branched primary alcohol ethoxylates, linear secondaryalcohol ethoxylates, branched secondary alcohol ethoxylates, polyalkylene oxide modified polydimethylsiloxanes, sorbitan derivatives,sodium alkyl aryl polyether sulfonate compounds, sodium alkyl arylsulfonate compounds trimethyl ammonium salts, and mixtures thereof. 4.The method of claim 1, wherein the silicone emulsion is selected fromthe group of Lambent Technologies E2175 emulsion, Lambent TechnologiesE2140 emulsion, Lambent Technologies E2140FG emulsion, Dow Corning HV600emulsion, Dow Corning 1664, Dow Corning 1101 emulsion, Dow Corning 346emulsion, General Electric SM 2068A emulsion, General Electric SM 2128emulsion, General Electric SM 2135 emulsion, General Electric SM 2138emulsion, General Electric SM 2140 emulsion, General Electric SM 2154emulsion, General Electric SM 2162 emulsion, General Electric SM 2163emulsion, General Electric SM 2167 emulsion, General Electric SM 2169emulsion, General Electric SM 2725 emulsion, Shin-Etsu KM 901 emulsion,Shin-Etsu KM 902 emulsion, Wacker Fluid Emulsion E10, and Wacker FluidEmulsion E1044, and mixtures thereof.
 5. The method of claim 1, whereinthe lubricant composition comprises: a. from about 0.0015 to about 50wt. % of a silicone material; and b. from about 50 to about 99.999 wt. %water.
 6. The method of claim 1, wherein the viscosity of the lubricantcomposition is less than about 40 centipoises when measured using aBrookfield viscometer with an RV2 spindle at a spindle speed of 20 RPM.7. The method of claim 1, wherein the lubricant is applied from a spraynozzle at a pressure of between 5 and 80 psi.
 8. The method of claim 1,wherein the lubricant composition is on for a period of time and off fora period of time and the ratio of off time to on time is at least 5:1.9. The method of claim 1, wherein the lubricant has less than 5% failurewhen measured using the PET compatibility test.
 10. The method of claim1, wherein the composition maintains an average coefficient of frictionof between about 0.05 and 0.25 over the entire period of use.
 11. Themethod of claim 1, wherein the lubricant composition is not dilutedprior to spraying.
 12. The method of claim 1, wherein the lubricantcomposition is diluted in line prior to use with a ratio of lubeconcentrate to water equal to between 1/5 and 1/1000.
 13. The method ofclaim 1, wherein the lubricant composition is substantially free oftriethanolamine salts of alkyl benzene sulfonic acid compounds.
 14. Themethod of claim 1, wherein the lubricant composition is substantiallyfree of an anionic surfactant.
 15. The method of claim 1, wherein thelubricant composition further comprises an additional functionalingredient selected from the group consisting of water misciblelubricants, hydrophilic diluents, antimicrobial agents,stabilizing/coupling agents, detergents and dispersing agents, anti-wearagents, viscosity modifiers, sequestrants, corrosion inhibitors, filmforming materials, antioxidants, antistatic agents and mixtures thereof.16. The method of claim 1, wherein the lubricant composition furthercomprises a water-miscible lubricant selected from the group consistingof a phosphate ester, an amine, an amine derivative, and mixturesthereof.
 17. The method of claim 1, wherein the lubricant composition isapplied to a first portion of the conveyor and maintains a firstcoefficient of friction and a second portion of the conveyor andmaintains a second coefficient of friction and the first coefficient offriction and the second coefficient of friction are not the same. 18.The method of claim 1, wherein the alkyl benzene sulfonic acid isdodecyl benzene sulfonic acid.
 19. A method for lubricating the passageof a container along a conveyor comprising applying an undilutedlubricant composition through non-energized nozzles to at least aportion of the conveyor, the lubricant composition comprising a siliconeemulsion selected from the group consisting of Lambent TechnologiesE2175 emulsion, Lambent Technologies E2140 emulsion, LambentTechnologies E2140FG emulsion, Dow Corning HV600 emulsion, Dow Corning1664, Dow Corning 1101 emulsion, Dow Corning 346 emulsion, GeneralElectric SM 2068A emulsion, General Electric SM 2128 emulsion, GeneralElectric SM 2135 emulsion, General Electric SM 2138 emulsion, GeneralElectric SM 2140 emulsion, General Electric SM 2154 emulsion, GeneralElectric SM 2162 emulsion, General Electric SM 2163 emulsion, GeneralElectric SM 2167 emulsion, General Electric SM 2169 emulsion, GeneralElectric SM 2725 emulsion, Shin-Etsu KM 901 emulsion, Shin-Etsu KM 902emulsion, Wacker Fluid Emulsion E10, Wacker Fluid Emulsion E1044, andmixtures thereof, and a water-miscible lubricant, the lubricantcomposition having a viscosity of less than 40 centipoise when measuredusing a Brookfield viscometer with an RV2 spindle at a spindle speed of20 RPM and the lubricant composition being substantially free of atriethanolamine salt of dodecyl benzene sulfonic acid.
 20. The methodaccording to claim 19, wherein the lubricant has less than 5% failurewhen measured using the PET compatibility test.